Continuous vacuum deposition apparatus



Sept. 30, 1969 c. J. BUKKILA ETAI- 3,469,550

CONTINUOUS VACUUM DEPOSITION APPARATUS 4 Sheets-Sheet Filed May 4. 1966Fig. 2b

INVENTORS CHARLES J. BU/(K/LA.

DONALD 7t EYBERG v JOHN s. LEM/(E RAYMOND M. OLSON AGENT Sept. 30, 1969-c. J. BUKKILA ETAL CONTINUOUS VACUUM DEPOSITION APPARATUS Filed May 4,1966 4 Sheets-Sheet L I 252 I H I82 90 240 34 I 242 Fly. 4 I l' 238 II IINVENTORS CHARLES .1. BUKK/LA 00mm T. EYBERG .flfll JOHN S. LEM/(ERAYMOND M. OLSON AGENT United States Patent 3,469,560 CONTINUOUS VACUUMDEPOSITION APPARATUS Charles J. Bukkila and Donald T. Eyberg,Mlnneapohs,

Minn., John S. Lemke, Phoenix, Ariz., and Raymond M. Olson, Minneapolis,Minn., assignors to Sperry Rand Corporation, New York, N.Y., acorporation of Delaware Filed May 4, 1966, Ser. No. 547,619 Int. Cl.C23c 13/04, 13/08 US. Cl. 118-6 Claims ABSTRACT OF THE DISCLOSURE Atri-stage continuous process evaporation system comprising loading,evaporating and unloading chambers, each chamber being independentlyevacuatable, with interconnection between chambers for the transfer ofsubstrates achieved by a tube-enclosed track system is described.Contained within the loading chamber is a mechanism for supporting andserially inserting a large plurality of substrates onto the trackleading to the deposition station. Similarly, the unloading stationincludes a mechanism for accepting the substrates from the track andstoring them in suitable cartridges.

This invention relates generally to a continuous vacuum depositionapparatus for handling substrates and depositing films of materials uponthem for forming memory elements.

More specifically, a continuous vacuum deposition system has beendeveloped to provide economical, reliable, and mass productioncapabilities for fabricating memory elements utilized for large capacityand high-speed computer memories. A memory element represents a basicbuilding block for a memory module. Such memory element may consist of asubstrate consisting of a thin sheet of glass onto which are depositeddiscrete magnetizable spots or bits of Permalloy or the like through agraphite or other substrate mask. There may be thousands of suchmagnetizable spots or bits in the order of .030 x .030 inch in size on asmall substrate. Other substrates and bit sizes may be required forparticular applications.

Structurally the present system comprises a loading and unloadingchamber interconnected through a vacuum deposition chamber, with thechambers being isolatable by valving means between the chambers.Prepared substrates in one embodiment are loaded into an indexablemulti-station cartridge substrate holder assembly or, alternatively, inanother embodiment into a single station cartridge substrate holder, inthe loading chamber. A track assembly interconnects the loading chamberand unloading chamber through the deposition chamber. A master controlunit controls handling and feeding of the substrates which aretransported along the track assembly through the system by controllingthe operation of a feeder assembly for supplying a substrate from thetop of a cartridge to the track assembly. After deposition, thesubstrate or memory element proceeds along the track assembly to theunloading chamber. The latter chamber, advantageously, contains all ofthe same substrate handling and storing structure as that contained inthe loading chamber. The only essential difference is in its mode ofoperation. That is, as a receiver of the substrates from the depositionchamber, its operational sequences are the reverse of thosecharacterized by the loading chamber. The deposited substrates orthin-film memory elements are subsequently stored in the unloadingchamber cartridges and ultimately removed from the chamber. The

3,469,560 Patented Sept. 30, 1969 master control unit controls allphases of operation in the system.

Known prior art vacuum deposition techniques do not provide continuousdeposition operations for the mass production of computer lmemories.While a variety of systems permit deposition of material upon continuousbelts unspooled and threaded through the system, no known systemsincorporate the unique features of the present invention wherein thereare utilized evacuatable loading, deposition, and unloading chambers,automatic feeding, indexing, deposition monitoring, and unloading meansfor the handling and processing of individual substrates on a massproduction basis. Simplicity of construction and operation among thecomponents of the system assure the reliability required for massproduction of memory elements. By the duplication of substrate handlingapparatus in the loading and unloading chambers substantial cost savingsin construction are further realized. As well, the duplication of theconstruction assure the further reliability of operation of allsubstrate handling apparatus. Accordingly, the design of the system isone possessing highly reliable mass production capabilities notheretofore recognized in the art. Otherwise complex problems of processand handling control are eliminated by the novel apparatus utilized.

In the fabrication of film memories, precautions must be taken tocontrol film characteristics and properties. Film properties such ascoercivity and anisotropy, for example, are parameters that can bematerially influenced by temperatures, pressures, degree of cleanliness,deposition rates and amounts, and the like. The present invention isdesigned to closely administer and control film handling and depositionoperations in order to provide a memory of desirable quality for presentday data processing equipment.

In modern computing equipment, memory capacity and speed of operation inthe ultra fast range are prime factors Weighing upon the effectiveapplication of the equipment. The present invention provides thecapabilities of achieving the requirements of such computer memories bymass production deposition apparatus incorporating novel structuralcomponents into an integrated system.

Accordingly it is a primary object of the present invention to provide acontinuous vacuum deposition system for the deposition of films ofmaterials upon substrates.

These and other more detailed objects of the invention will be moreevident by the specification and drawings, in which:

FIGURE 1 is a schematic exemplary illustration of three interconnectedstages of the vacuum deposition system of the present inventionincorporating loading, deposition, and unloading chambers.

FIGURE 2a is a side sectioned view of one embodiment of a portion of thesystem invention incorporating a multi-station indexable type substrateholder in the loading chamber and as likewise used in the unloadingchamber, although not shown with the latter in the view, together withthe track and bridging assemblies for transporting substrates to thedeposition chamber.

FIGURE 2b is a side view in section illustrating track assemblies fortransporting through the vacuum deposition chamber. FIGUR'ES 2a and 2bare composite views to be taken together with the track assembliesconnected.

FIGURE 3 is a top view of a portion of the apparatus in FIGURE 2aincluding the multi-station indexable substrate holder and the track andbridging assemblies.

FIGURE 4 is a side sectioned view of an alternative embodiment of thepresent invention incorporating a single station non-indexable typesubstrate holder in the loading chamber and as likewise used in theunloading chamber, although not shown with the latter in the view,together with the track and bridging assemblies.

FIGURE 5 is a top view of the apparatus of FIG- URE 4.

FIGURE 6 is an enlarged end view of the bridging assembly taken alongline 6-6 of FIGURE 4.

FIGURE 7 is a side view of a puller arm and finger associated with theunloading chamber apparatus of both embodiments.

FIGURE 1 represents a schematic illustration of the vacuum depositionsystem of the present invention. Although a three stage system is shown,no limitation is made thereto. The system includes a loading stage 10,deposition stage 160, and unloading stage 162, all of which areevacuatable and the apparatus associated therewith is coupled to thecontrol unit 11 which maintains a controlling influence on all theoperations performed.

FIGURE 2a, shows an evacuatable loading chamber or stage 10. The chamberis defined by walls 12, base plate 14, and a removable cover portion 16.Preferably, although not necessarily, the chamber is con structed ofstainless steel in order to prevent outgasing of material which wouldotherwise be adsorbed and/or absorbed on or in the chamber constructionitself. A seal member 18 near the top of the chamber 10 is adapted tofit to the walls 12 while a second seal 20 in contact with seal 18associated with the cover 16 effectively seals the chamber under vacuumconditions. The chamber 10 ispreferably circular in design, although notnecessarily restricted to such shape. In an upper region of the chamberthere is located a vacuum inlet port 22 communicating internally withthe chamber and connected to a suitable vacuum producing source (notshown). An outlet port 24 communicating internally with the loadingchamber is adapted to receive various structural components to bedescribed below. The base plate or bottom plate 14 is provided with twofeedthroughs 26 and 28' for accommodating a lead screw and gear drivearrangement. The feedthroughs are sealed to the base plate by sealhousings 30 and 32, respectively for preventing loss of vacuum.

Still referring to FIGURE 2a, a lower half of a ballrace element 34 issuitably secured to the base plate. The race element as shown is annularin configuration and contains along a top surface 36 thereof a recessedgroove 38 for accommodating spherically-shaped ball elements 40. Theball elements are fabricated of such material such as stainless steel inorder to withstand stress under load and because of their suitableproperties under vacuum conditions.

Also secured to the base plate 14 such as by welding or the like is apin mount 42. A vertically projecting position retaining pin 44 has oneend thereof 46 fixedly secured within a recess in the mount 42. The pin44 projects upwardly as shown for a predetermined distance for a purposewhich will be described infra.

A vertically oriented lead screw 48 is disposed centrally of the loadingchamber. At a bottom end thereof the shaft is fixedly secured to onehalf 50 of a magnetic coupling member. The coupling member consists of alarge block of non-magnetic material containing or mounting thereinselectively disposed magnets. The larger of the two feedthroughs, 26,projects downwardly of the base plate 14 and in its lower regionscontains therein the magnetic coupling member 50. Feedthrough 26 isprovided with a flanged portion 52 adapted to receive a plate member 54sealed by a sealing means 56 to the flange. As shown, the plate member54 and its seal completely close off the feedthrough 26 from the ambientenvironment to maintain a desired vacuum level within the chamber 10.

Disposed externally of the feedthrough 26 and magnetic coupling member50 is the driving half 58 of the magnetic coupling suitably connected toa shaft '60 and driving source not shown. As with coupling member 50,coupling member 58 has magnets disposed therein; however havingcorresponding poles of opposite polarity. As coupling member 58 isrotated, coupling member 50 is forced to rotate the lead screw.

It is to be understood that the magnetic coupling drive configurationcould be replaced by a shaft extending through a suitable seal means.The magnetic coupling is preferable, however, because it deletes anysealing prob lems that may be caused by projecting a rotatable shaft tothe ambient environment. It is preferable to substitute a drivingarrangement not utilizing a rotating member projecting into a vacuumchamber because of the danger of introducing impurities from the sealand ambient impurities when the seal becomes worn.

Proceeding with the description, vertically oriented leadscrew 48 hasgrooves along its periphery beginning at a lower portion thereof.Cooperating therewith is a vertically positionable lead screw mechanism61 also well known in the art. The mechanism consists of a flange member62 and a ball retainer housing 64 having disposed therein suitablefollower means such as balls or the like for guiding the screw mechanismup and down the lead screw 48 when the latter is driven through themagnetic coupling. Secured to the flange member 62 such as by screws 66or the like is a pallet member or arm 68. Since the pallet arm issecured to the flange member 62 it is likewise caused to translatevertically in the chamber. The pallet arm contains a hole 69, thefunction of which will be described subsequently.

The pallet arm 68 projects through an opening in the substrate holder 70which is a part of the rotatable indexer assembly 72. The indexerconsists of a base member 74 having an annular configuration as shown.An upper ball race element 76 is secured to the bottom of the basemember 74 such as by screws or the like. The ball race element 76 likethe ball race element 34 has a recessed groove extending around itssurface for accommodating the balls 40 aforementioned. Extendingentirely around a flange portion 78 of the ball race are gear teeth 80the use of which will be described in the ensuing description.

The base member 74 has an upwardly projection portion 82 completelyaround its periphery. Secured to a top surface thereof by mountingscrews 86 or the like are the substrate holders 70 which contain thesubstrates. The holders form a portion of the entire indexer assembly72, of which there are preferably six holders in number, although moreor less may be accommodated as desired.

Referring at the same time to FIGURE 3, it can be seen that thesubstrate holders are defined by side walls 86 forming a partial backwall portion 88, and a partial substrate holder base plate 90. Althoughonly two substrate holders have been shown in FIGURE 2a for purposes ofclarity, a greater plurality are disposed around the base member 74,preferably six of them as shown in FIGURE 3. A top support 92, shown inFIGURES 2a and 3, consists of a plate having Y-like extensions 93 havingdown turned end portions 95 secured to wall portions 88, which maintainsthe substrate holders in a top supported condition with respect to theindexer assembly. It can be seen that the plate 92 is the supportingstructure for the upper part of the substrate holders.

The top plate 92 is in turn journaled in a bearing-like element 94supported by a shaft terminal portion of lead screw 48 at its uppermostend. The bearing 94 contains a recess or notch around its periphery forreceiving the top plate 92 therein. Therefore, as lead screw 48 rotates,it rotates in the bearing 94.

Referring now to the lower end of the loading chamber, there is shownthe second feedthrough 28 along with its seal arrangement. Secured toone end of the drive shaft 98 is a driving gear 100 having gear teeth102 disposed around its periphery. The gear teeth 102 mesh with gearteeth 80 of the upper ball race driving gear 76. Disposed at a lower endof the drive shaft 98 and secured to it is a magnetic coupling member104. Disposed externally of the feedthrough and plate is the drivinghalf of the magnetic coupling for effecting rotation of the shaft 98 andis the same construction as that of the magnetic coupling associatedwith the lead screw 48 above mentioned.

Referring to FIGURE 20!, the lead screw mechanism 61 and pallet arm 68are shown in their uppermost translational position by phantom lines andin the lower most translational position in full lines. It can be seenthat when the mechanism is in its lower most position, the pin 44projects through the hole 69 in the pallet arm for preventing rotationof the arm as the indexer assembly 72 is indexed.

It is to be noted that a clearance area 109 between the bottom plate 90of the substrate holders and the indexer base plate 74 is provided topermit room for the pallet arm below the substrate holders 70 when theindexer is rotated. That is, the pallet arm is in a position ofnoninterference with the indexer assembly.

Magnets 106 and 107 are secured to the lead screw assembly 62 fortranslation therewith. A support post 108 may be secured to the internalperiphery of the ball race element 34 and projects upwardly in thechamber. At its lower and upper end the post may mount conventional reedswitch elements 110 and 112 or the like. As can be seen, when the leadscrew assembly achieves its uppermost excursion, the magnet 106 affectsthe switch element 110 to signal a master control unit (shown in FIG-URE 1) to effect reversal of rotation of the lead screw 48.Consequently, as lead screw 48 lowers the lead screw assembly, themagnet 107 affects the switch element 112 at that extreme excursion toterminate rotation of the lead screw until the master control unitsignals the substrate indexer assembly to index. Then the operation ofraising the pallet arm re-commences.

Operational mode of entire assemblies An operation of the structuraldescription thus far illustrated is briefly set forth. The magneticcoupling associated with the larger feedthrough drives the lead screwwhereby the lead screw mechanism translates vertically whilesimultaneously raising or lowering the pallet arm, depending upon thedirection of rotation. As the screw rotates, intermittently, an ejectormechanism to be described ejects substrates from the top of the stack inthe substrate holder and ejects them from the loading chamber onto atrack assembly also to be described. Assuming that the pallet arm hasbeen raised to its uppermost position by the lead screw, the upper limitswitch is actuated whereby lead screw rotation reverses to lower thelead screw assembly and pallet arm to a lower most position untilanother limit switch terminates lead screw rotation. At this point thepallet arm is entirely below the substrate holders in the clearance areadesignated. Subsequently, the driving mechanism associated with thesmaller feedthrough is actuated to drive the ball race driving gear.Since the indexer base member is secured to it, rotation of the gearrotatably indexes the indexer to the next filled substrate holderposition whereupon the indexer is caused to stop. During the indexingsequence, the pallet ann remains in a stationary or non-rotatableposition by reason of the pin projecting through the hole in the palletarm. As these sequences come to an end, the lead screw assembly onceagain is driven to lift the stack of substrates in the holderintermittently until one by one they are picked from the stack andejected from the loading chamber onto the track assembly.

Having completed a detailed description of the mechanisms in the lowerhalf of the loading chamber, the ensuing description relates to theejecter assembly located in the upper approximate half of the chamber.Referring to FIGURES 2a and 3, there are shown side and top viewsrespectively of the entire assembly.

A second lead screw 114 horizontally disposed and a lead screw mechanism116, similarly constructed to that for raising and lowering the palletarm are utilized. For facilitating assembly of the lead screw 114 andlead screw mechanism 116 into the chamber or disassembly therefrom, ashaft coupler 118 has a recess in coupler therein. The recess 118receives a portion of the lead screw 114 and is secured thereby by anadjustment screw 126 or the like. A recess 128 in the feedthrough isadapted to receive a driving source suitably sealed therein to precludevacuum loss and is interconnected to the coupler 118. The couplerfurther permits complete removal of the indexer from the loadingchamber. For convenience of illustration a conventional shaft-througharrangement is shown.

It is to be understood, that by the use of the aforementioned magneticcoupling as well as with the illustrated arrangement, with adequatesealing precautions and a sufiiciently large port, the lead screw andlead screw mechanism could be removed therethrough and the couplerfeature 118 deleted. A variety of suitable driving arrangements could beutilized and is believed to be within the skill of the routine designer.

At its other end lead screw 114 proceeds through outlet port 24 of theloading chamber to a mounting 130 secured such as by welding to theinternal surface of the port 24 near gate valve 132. A hearing 134 isdisposed in the mounting and receives the terminal portion 136 of thescrew therein. The lead screw 114 is rotated by the driving source (notshown) above mentioned. A guide member 138 preferably having a guidewayopening or slot 148 along its length is secured to posts 140 and 142secured such as by welding to the loading chamber walls. The guidemember 138 is in turn secured to the posts at both ends thereof byscrews or dowels 144 or the like. By using dowels, for example, removalmay be effected with facility by merely lifting up and out of theloading chamber. A lever 146 is rigidly secured at one end to the leadscrew mechanism 116. Near its opposite end a guide stud 150 is securedto lever 146. Preferably, although not nec essarily, guide stud 150 isof circular cross-section in order to reduce friction in the guideway.As the lead screw mechanism traverses horizontally along the lead screw,it is prevented from turning on its axis by reason of the guide wayrestraining rotational motion by reason of the guide stud 150 and lever146 secured to the lead screw mechanism.

Suitably attached to the guide stud are pairs of magnets 125 and 127 andsuitably mounted at both ends of the guide member 138 are limit switchelements 129 and 131. As the ejecter lead screw mechanism traversesalong the lead screw in either direction, its excursion is limited bythe magnets 125 and 127 actuating the limiting switches, which may, forexample be reed switches or the like whose contacts are affected wheninfluenced by the magnets in the proximate vicinity. As the limitswitches are actuated, the lead screw 114 is caused to reverse itsdirection of rotation under the influence of the lead screw drivingsource. The lead screw mechanism then returns to a starting position inpreparation for the next substrate ejection cycle.

An ejecter arm 152 is fixedly secured in a suitable manner to the leadscrew mechanism. Disposed at its opposite end is a finger 156 forejecting the substrates from the top of the stack in the substrateholder 70 to a track assembly 158 to be described next.

The track assembly 158 is used to transport substrates from the loadingchamber 10 to vacuum deposition chamber or station means 160 of whichthere may be a plurality; however, only one being shown. From thedeposition chamber the substrates are transported to the unloadingchamber 162. Interconnecting each of the chambers are tubes forcontaining the track assembly. The tubes interconnecting the chambersadditionally contain preheaters to affect a.bake-out process and may beconstructed with a cooling jacket in the portion extending from thedeposition chamber to the unloading chamber to reduce the temperature ofthe memory element. A short section of track assembly is mounted in theoutlet port 24 of the loading chamber and extends to a gate valve 132,the details of which are not necessary. A bridge assembly 164 spans thegap in the gate valve and will be described subsequently. From the righthand side of the gate valve 132 a track assembly portion 159 proceeds tothe deposition chamber (see FIGURE 2b).

Referring in greater detail to FIGURE 2a, there are secured to theinternal periphery of the outlet port 24 block members 170. The blockmembers are preferably welded along an internal arcuate portion to theport. Holes are disposed in the block members 170 to permit widening ofthe track assembly for certain applications as will be explainedsubsequently. Disposed upon the top surface of each of the block members170 are L-shaped guide blocks 174 fixedly secured by screws 176; andsecured to the top surface of the guide blocks by screws 178 are smallL-shape adjustment blocks 180 preferably welded at a back surfaceportion thereof to the individual channel tracks or rails 182. Spacedalong the tracks at spaced intervals are spherically shaped rollers orballs 184 mounted on screw axles threaded into the rails. Preferably theaxles and balls are made of stainless steel for the reasons mentionedabove. The balls rotate fully on their axles to permit transport of thesubstrates along the top of the rollers. A cross member 186 having aslot therein extends across the top of the tracks and is secured theretoby screws 188.

In order to accommodate wider substrates, screws 176 and 188 areloosened to permit outward movement of the tracks along thecross-member. The screws 188 m ve along the slot in the cross-member.Likewise L-shaped blocks 174 are moved outwardly and screws 176 locatedin a different hole nearer the pehiphery of the tube. For that matter,the holes for screws 176 could be replaced by a slot such that when thescrews are loosened and when the tracks are moved outwardly, theL-shaped block members 174 slide along the top surface of the blockmembers 170.

When a new supply of substrates is to be inserted into the loadingchamber, gate valve 132 is closed so as to isolate the vacuum depositionchamber 160 from the loading chamber. In this way the deposition chamberremains unaifected during the loading operation into chamber 10. As canbe seen from FIGURES 2a and 3, a bridging section 164 bridges the valvegap area. Obviously, when the valve is closed to isolate chamber 10, thebridging section 164 must be positioned to a non-interfering position.Referring to FIGURES 2a and 3, the bridging section 164 is pivotallymounted to permit its movement to a non-interfering position in the gatevalve 132. As the valve (not shown) is closed, it contacts the bottom ofthe bridging section. As the valves continue to close, the bridgingsection pivots counterclockwise to a completely retracted positionwithin the flange of the gate valve 132. The bridging section is shownin detail in FIGURES 5 and 6. The pivoting portion thereof consists ofplate member 190 having a downwardly extending lip at each end thereofat 192. The leading edge thereof may be rounded and is provided with astop tab 194 secured to a bottom surface of the top plate and projectingbeyond the curvature. The top tab 194 limits the clockwise pivotalmotion of the bridging section by abut. ting the cross stop bar 196interconnecting the rails in the track section 159 to the right of gatevalve 132 leading to the vacuum deposition chamber. A cross bar 198 ofthe bridge assembly extends transversely underneath and has upturnedportions 200. Adjustment plates 202 are securred to the cross bar andcontain notched-out portion or slot 202 for receiving adjustable memberssuch as screws received by threads in the tracks. By loosening thescrews the rails can be brought closer together or spaced further apartfor receiving different size substrates. The bridge assembly ispivotally supported by shaft 204 rotatably secured to the flanges of thecross bar 198 at either end thereof. Spacer members 206 are disposedbetween the bridge and the upturned flanges to transversely maintain theposition of the bridge assembly. Arms 208 are mounted at one end uponthe shaft 204 and are held against the downwardly extending lips of thebridge plate member 190. The arms extend upwardly above the surface ofthe plate member and act as lateral guides for the substrates as theymove over the surface of the plate member across the bridge assembly.

The section of tubing interconnecting the loading chamber to thedeposition chamber contains heating members 210 for effecting what isknown in the art as bake-out. During this process the substrates areheated by the members 210 which are preferably fused quartz lamps withreflective shields 211 shown schematically in FIGURES 212 for purposesof clarity. During this process the temperature of the substrates israised to a high temperature to drive off absorbed and adsorbed gases inthe substrates. The heater elements are suitably interconnected throughthe tube by a feedthrough (not shown) with a power source disposedexternally of the system. The track assembly section 159 is disposed inthis section of tubing; however is mounted differently at the pointwhere the track resumes on the right hand side of the gate valve 132shown in FIGURE 2a. As aforementioned, block members are secured to theinternal periphery of the tubing. Similarly, L-shaped guide blocks 174are seated on and adjustably secured to the guide blocks, and as before,adjustment blocks 180 are secured to the tracks at their back surface.However, an additional feature is incorporated which is the use ofsupport studs 214 having a truncated cone or chamfered enlargement 216adapted to be received in a mating recess 218 disposed in the L- shapedguide blocks. This configuration is not intended to be limitive innature since a variety of suitable mounting arrangements may beutilized. As before, blocks 174 may be repositioned to spread the tracksapart. The present configuration facilitates insertion of the entiretrack assembly 159 into the tubing during the assembly operation. Thetrack assembly is merely positioned until the support studs are alignedwith their respective recesses, and then the assembly drops into anonmovable position. The track section 159 from the right side of gatevalve 132 to the deposition chamber likewise represents one continuousunit. A similar mounting arrangement is made for this section of thetrack assembly in the inlet port 220 of the deposition chamber with theexception that block member 175 can accommodate two support studs 214. Aseparate track section 222 is located in the deposition chamber itself.The left end portion thereof seats in the block 175 while the other endof track 222 seats in a like manner in a block 175 located in the outletport 228 thereof.

Within the deposition chamber there are disposed various apparatus foreffecting the deposition of desired films of materials upon thesubstrates and devices for monitoring the process. For example, separatesources for the evaporation of SiO, Permalloy and copper may be disposedwithin the deposition chamber. Although specific descrip tion as to theapparatus is not referred to herein, it is to be understood that sameare utilized to produce the ferromagnetic films upon the substrates. Forexample, apparatus such as an electron beam gun, feeding apparatus, andmonitoring devices also are disposed in the chamber. For convenience ofillustration 224 represents the schematic incorporation of suchnecessary features to produce memory elements.

Inasmuch as the system is substantially symmetrical both in structureand operation, that is, the tubing, track assembly sections, gate valve,bridging section, and unloading chamber also appear on the right oroutput side of the deposition chamber illustrated in FIGURE 2b, noadditional illustrations are considered necessary. The output tubing maybe provided with a jacket to permit circulation of a cooling mediumtherein so that the substrates are cool upon reception in the unloadingchamber. A particularly advantageous feature of the present invention isthe duplication of the structures contained within the loading chamber10 and unloading chamber 162, the only modification made is with respectto the puller arm 230 and finger 232. By way of reference to FIGURE 7there is shown the arm and finger. It is evident that the ejecter arm inthe loading chamber 10 ejects the substrates onto the track assemblywhile the ejecter arm and finger associated with the unloading chamber,herein termed a puller arm and puller finger, function to withdraw thesubstrates from the track assembly. The finger 232 is hinged at 234 topuller arm 230. Accordingly, as the arm completes the withdrawal of athin-film memory element the associated lead screw reverses to reversethe direction of translation of the lead screw mechanism translatingtherealong. As the puller arm enters the output port of the unloadingchamber 162, the finger 232 pivots counterclockwise and when the leadscrew reverses its direction of rotation again, the finger contacts thetrailing edge of a memory element and withdraws same along the bridgingand track assemblies to the substrate holder being filled at this pointwith the memory elements.

The unloading chamber contains all of the same structural aspects of theloading chamber; therefore, no detailed description or illustrations aremade. It is to be understood, however, that the sequence of events arethe reverse of that described with respect to the loading chamber.Instead of the pallet arm lifting substrates upwardly in the substrateholder, the pallet arm lowers an incremental distance under the reversedriving direction of its lead screw. When one substrate holder orcartridge is completely filled, a limit switch corresponding to lowerlimit switch in the loading chamber 10 is actuated to cause the drivegear associated with the ball race element to rotate the indexer apredetermined number of degrees whereby an unfilled substrate holderaligns itself with the track assembly. The unloading operation continuesuntil all the substrates or as many as desired have been withdrawn. Thenthe gate valve similarly constructed as gate valve I32 is closed and itsbridging section raised to completely isolate the unloading chamber fromthe deposition chamber. The top cover is removed from the unloadingchamber and the substrates removed. Upon emptying the substrate holders,the top cover is replaced, the unloading chamber pumped down to thedesired vacuum level, and the gate valve opened, and its bridgingsection disposed in a spanning relationship.

As described above, the structural assemblies within the loadingchamber, the vacuum deposition chamber, and the unloading chamberfunction in a specific sequence of events. To control all of theoperations a master control unit (FIGURE 1) is electrically coupled tothe system. The master control unit prescribes the timing andoperational prerequisites for specific series of events.

Operation Assuming now that the loading chamber substrate cartridgeshave been fully loaded and the entire system evacuated to prescribedlevels, the magnetic coupling associated with the loading chamber isenergized whereby the lead screw begins to raise the pallet arm with thesubstrate. Assume that the ejecter assembly is completely retracted to astarting position. The control unit energizes the horizontal ejecterlead screw shaft whereby the ejecter arm moves toward the track assemblyand removes a single substrate from the stack. The ejecter arm iscontinually advanced until the trailing edge of the substrate clears thebridging section into the heating tube. As the magnets on the guide studcome into a position in proximity to the switch elements, switchingcircuitry coupled thereto effects reverse rotation of the lead screw. Asthe lead screw mechanism retracts from the track assembly, the magnetsof the guide stud move into proximity with other switch elements on theother side of the chamber. Upon opening the circuit to the ejecter leadscrew driving source, the lead screw stops rotation. The control unittransmits a command pulse to the driving source associated with themagnetic coupling in turn associated with the pallet raising lead screw.As the lead screw rotates, a new substrate is disposed in alignment withthe ejecter arm pawl. After a predetermined time interval, the controlunit issues a command to stop rotation of the lead screw. Anothercommand is made to once again energize the ejecter lead screw whichtranslates the ejecter arm to remove the topmost substrate fordisposition in the track whereupon the ejecter lead screw retracts theejecter arm to a start position. The operation continues to functionuntil the inlet port and the vacuum deposition chamber have beenfilled-and with one or more substrates disposed within the depositionchamber itself. The carriers containing the substrates are pushed end toend through the system over the rollers. The control unit then issuescommands to the various deposition apparatus. Whenever a substrateholder has been emptied of substrates, the control unit signals the ballrace drive gear to rotate the indexer one substrate holder position.Prior to such rotation the pallet arm has been returned to the clearancearea beneath the substrate holder so as to be in a non-interferingposition. The indexing proceeds from one emptied substrate holder to thenext until all have been removed after which a new charge is insertedinto the loading chamber. Upon receipt by the control unit ofinformation indicating that the substrate deposition has beensatisfactorily completed, the ejecter driving source is again energizedto deposit one or more substrates into the track assembly. Likewise,when the completed thin-film memory elements in their carriers aretransported to the unloading chamber, the puller assembly under thecontrol of the control unit removes the memory elements and disposessame into the substrate holders. The indexer and puller lead screwdrives are rotated at the proper times to withdraw the memory elements,fill up one substrate holder, and index to an unfilled holder.

It can be seen then, that the control unit maintains strict control ofall processes and operations in order to assure proper function of allsystem components required to be operated at a particular time and overa particular time interval.

Referring now to FIGURES 4 and 5, there is illustrated an alternativeembodiment for the equipment in the loading and unloading chambersincorporating a nonindexable single station substrate cartridgeconfiguration.

In order to preserve clarity the loading chamber housing or containerwith the exception of the bottom plate has been deleted. Likewise, theentire ejecter assembly, and so on has been deleted since it is the sameas in FIGURE 2a. Turning now to the bottom of FIGURE 4, there arepartially shown the magnetic drive coupling housings which are the sameas that shown in FIGURE 2b. Likewise the vertical lead screw, and leadscrew assembly are the same as that illustrated in FIGURE 2b.

Disposed upon the base plate 14 is an annular ring member somewhat likethe ball race member of FIGURE 2b. However, in this instance the ballsand groove are not utilized because of the single cartridge feature notrequiring indexing. Accordingly, the upper half of the race member isdeleted. Referring simultaneously to FIGURE 5 there is shown a top viewof the substrate holder and lead screw assembly. Secured to the baseplate 14 is the pin holder 42 for fixedly securing at one end thereinthe pin member 44. All of the previous is the same as in FIGURE 2a.Suitably secured such as by screws and the like to the annular ringmember 34 are support posts 236 and 237 projecting upwardly in thechamber. Secured to the top surface of the annular ring member 34 issupport plate 238 corresponding to plate 74 in FIGURE 2b and containingopenings therein so as to reduce pumping requirements in the chamber.Supported at one end thereof are support posts 240 and nearer the centerare support posts 242. Disposed and suitably secured to the posts 240and 242 is substrate holder base plate member 244 having an enlargedopening 246 to permit pallet arm 68 to raise up and down into and out ofthe substrate area. Substrate holder 70 is constructed in a manner tothat illustrated in FIGURE 2a. To support the upper end of the substrateholder 70, top support plate 252 is secured such as by screws or weldingand the like to the substrate holder back wall portion and secured tothe vertical support posts 236 and 237 and further supported by thevertical lead screw shaft in journal bearing 248 the top support plateis suitably secured to a bottom surface of the journal housing 250. Asshown then, the top surface plate supports the upper end of thesubstrate holder by its interconnection at one end to the substrateholder and at its other end to the journal housing while the shaft ispermitted to fully rotate within the journal bearing 248.

In the immediate configuration, the track assembly is supported in theoutlet port 24 in the same manner as in FIGURE 2. However in the presentconfiguration, track extension arms 254 secured at one end to the tracksare secured at the other end to the substrate holder walls at 256 toprovide additional support for the substrate holder 70. Screws or thelike may be used for the tie-down. In order to provide for reversal ofrotation of the pallet arm lead screw, magnets and limiting switches areutilized in a manner similar to that shown in FIG- URE 2a. The flange ofthe vertical lead screw assembly (not shown) mounts, for example, twomagnets as in the previous embodiment. An upper switch element intranslational alignment with one magnet is mounted on a holder 258 tothe annular ring member. Another and lower switch element intranslational alignment with the other magnet is projected by a hanger260 or the like from the top plate 252. Accordingly when the lead screwassembly raises the pallet arm to its upward most excursion at whichpoint the last substrate is positioned in alignment with the ejector andtrack, the upper limit switch is actuated to cause reversal of operationof the lead screw after the last substrate has been sent on its way tothe vacuum deposition chamber. As the pallet arm lowers, the lower limitswitch is actuated to cut-off power to the magnetic coupling device.Then the substrate holder is reloaded with a fresh charge of substratesand the operations repeated.

Again as in the other embodiment, the unloading chamber contains thesame structure as that contained within the loading chamber. Likewise apuller arm and finger removes the memory elements from the outlet trackassembly and loads them into the cartridge. All track sections andbridging assemblies are constructed as those illustrated in the figures.

Inasmuch as the master control unit operates principally, the same asaforementioned, no further explanation is considered necessary. Theessential difference is that the control unit need not provide theindexing control function for the substrate since the immediateconfiguration is not rotatable.

It can be seen then that the only changes in the immediate configurationare those in the loading and unloading chamber. When it is desired toload a great number of substrates, the covers of the loading andunloading chambers are removed, the assemblies removed and the indexingcarrier inserted. Accordingly, the interchange feature permits increasedcapacity for specific applications. As a practical matter, where theapplication of the invention does not require an indexable multi-stationsubstrate holder, the latter is merely removed from the loading andunloading chambers and the single station substrate holder inserted as aunit. The upper ball race element is removed and the new substrateholder base plate is screwed down to the bottom race element disposed onthe base plate.

It is to be understood that the present invention is not limited to theuse of only a single deposition, loading, and

unloading chamber. The system is capable of accommodating an expansionwhereby additional chambers may be utilized as needed for particularapplication.

What is claimed is:

1. In a system for depositing selected materials on predetermined areasof substrates for producing memory elements, substrate handlingapparatus comprising: loading stage means including a first chambercapable of being evacuated, and substrate transport means for selectingindividual ones of a plurality of substrates for processing, saidsubstrate transport means including first substrate support means forsupporting the selected substrates; processing stage means including asecond chamber capable of being evacuated for processing saidsubstrates, said processing stage mean including second substratesupport means; unloading stage means including a third chamber capableof being evacuated, and processed-substrate transport means for stackingand retaining processed substrates, said processed-substrate transportmeans including third substrate support means for supporting saidprocessed substrate prior to being stacked; first tube meansintermediate said loading stage means and said processing stage meansfor permitting said substrates to be moved from said loading stage meansto said processing stage means; first valve means mounted in said firsttube means, said first valve means including first bridge means having afirst position for coupling said first substrate support means to saidsecond substrate support means for permitting said substrates to besequentially moved from said loading stage means to said processingstage means, and first closing means for closing ofi said first tubemeans for isolating said processing stage means from said loading stagemeans for loading additional substrates, said first bridge means havinga second position for decoupling said first substrate support means fromsaid second substrate support means when said first closing means isoperative to close off said first tube means; second tube meansintermediate said processing stage means and said unloading stage meansfor permitting said substrates to be moved from said processing stagemeans to said unloading stage means; and second valve means mounted insaid second tube means, said second valve means including a secondbridge means having a first position for coupling said second substratesupport means to said third substrate support means for permitting saidsubstrate to be sequentially moved from said processing stage means tosaid unloading stage means, and second closing means for closing offsaid second tube means for isolating said processing stage means fromsaid unloading stage means when unloading said processed substrate, saidsecond bridge means having a second position for decoupling said secondsubstrate support means from said third substrate support means whensaid second closing means is operative to close otf said second tubemeans.

2. The invention of claim 1 wherein each said loading stage means andunloading stage means include:

(a) indexable multi-station substrate holder assembly means.

3. The invention of claim 2 wherein said first, second and thirdsubstrate support means includes:

(a) parallel guide means;

(b) adjustable means to permit lateral spacing of the guide means;

(0) roller carrier means rotatably supported by each of said guide meansfor transporting the substrates therealong.

4. The invention of claim 2 wherein each said indexable assembly meansincludes:

(a) a plurality of substrate stack containing compartments;

(b) supporting means for supporting said indexable assembly means;

(c) feeding means for movably supporting a substrate stack;

(d) and driving means coupled to a first driving source and cooperatingwith said supporting means intermittently for indexing said indexableassembly means one compartment at a time after one compartment isemptied of substrates.

5. The invention of claim 4 including:

(a) an ejecter and puller assembly means mounted in said system andassociated respectively with said loading stage means and said unloadingstage means for removing substrates individually from the substratestack and for supplying substrates individually to form a substratestack, said last named stack being formed in said unloading stage means6. The invention of claim 5 wherein said ejector assembly meanscomprises.

(a) a second rotatably supported shaft member supported in said systemand extending transversely and above the other rotatable shaft member,the second shaft member being aligned with said substrate support means,said second shaft member being coupled to a third driving source;

(b) a second translatable assembly operatively coupled to said secondshaft member;

(c) and ejector arm means connected to said second translatable assemblyfor engaging a substrate at the top of the stack and ejecting saidsubstrate into said substrate support means upon movement of said secondtranslatable assembly toward said substrate support means.

7. The invention of claim 6 including:

(a) motion limiting means associated with each of said translatableassemblies for limiting movement of said translatable assemblies, saidmotion limiting means being respectively electrically coupled to thesecond and third driving sources and to a control means coupled to saidtranslatable assemblies to effect a predetermined sequence ofoperations.

8. The invention of claim 4 wherein said feeding means comprises:

(a) a rotatable shaft member, said shaft member being connected to asecond driving source;

(b) a first translatable assembly operatively coupled to said shaftmember; (c) and an arm member secured to said translatable assembly,said arm projecting into a holder compart- 5 ment for lifting said stackwhen said shaft member is rotated.

9. The invention of claim 8 wherein said means for supporting saidindexable assembly comprises (a) a substrate holder support base means,said substrate holders being secured to said support base means;

(b) and a ball-race assembly having an upper and a lower portionseparated by roller elements to permit relative rotation between theupper and lower portions, said upper portion further having gear teetharound a periphery thereof, and said upper portion being secured to thesupport base means.

10. The invention of claim 9 wherein said driving means comprises:

(a) a second shaft member connected to a second driving source, adriving gear secured to said shaft and engaged with said teeth wherebyrotation of said driving gear causes rotation of said upper portion andindexing of said substrate holder assembly means.

References Cited UNITED STATES PATENTS 1,060,007 4/1913 Matthews 2212302,334,124 11/1943 Peterson 214-34 2,652,161 9/1953 Herzig 221792,834,510 5/1958 Cenotti 22179 3,314,395 4/196'7 Hemmer 117107 3,340,1769/1967 Belluso et a1. 11850 35 ALFRED L. LEAVIT'I, Primary Examiner W.E. BALL, Assistant Examiner U.S. Cl. X.R.

